Westport Water Supply S Griffin Public Meeting March 14 th 2013 - - PowerPoint PPT Presentation

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Westport Water Supply S Griffin Public Meeting March 14 th 2013 - - PowerPoint PPT Presentation

Jan 17, 2024 18 likes •459 views

Westport Water Supply S Griffin Public Meeting March 14 th 2013 Outline of presentation Brief history of water supply Issues of recent times Asset management of existing supply and reticulation S trategic Review of Water S

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Westport Water Supply

S Griffin Public Meeting March 14th 2013

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Outline of presentation

  • Brief history of water supply
  • Issues of recent times
  • Asset management of existing supply and

reticulation

  • S

trategic Review of Water S upply

  • Final Options from the peer review
  • Treatment Plant Upgrade – Opus
  • Costs
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Purpose of the upgrade

  • To provide a safe and secure water

supply for Westport for the next 50 to 100 years

  • To restore consumer confidence with a

water supply that has no taste and odours

  • A water supply that meets the Drinking

water standards

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History

  • Water supply constructed 1903
  • Water Treatment plant constructed 1985
  • Maj or Upgrade to commence 2013/ 14
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  • Tunnel collapse in 2000 resulted in first

strategic investigation

  • Connell Wagner engaged to look at all

aspects of existing supply and also other potential sources

  • Risk of tunnel collapse was quantified –
  • utcome was the construction of

alternative pump supply – cost about $1m

  • Water pumped from lower reaches of

Orowaiti introduced algae to reservoirs – a possible source of the taste and odour

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  • Further tunnel collapse resulted tunnel

being piped $600,000

  • Backwash failure resulted in the residual

reservoir material being piped into the town reticulation.

  • S

econd occurrence almost 12 months later

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Main Replacements

  • Main trunkmain varies in age
  • To replace a 454mm pipe means minimal

water or to some residents none at all 2003/ 04 - 10 pipes 2004/ 05 – 5 pipes 2005/ 06 – 6 pipes 2006/ 07 – 5 pipes 2007/ 08 – 7 pipes 2008/ 09 – 1 pipe 2010/ 11 – 11 pipes 2011/ 12 – 2 pipes To some consumers these breaks occur too often.

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Reticulation &Pressure

  • Like the trunk main the reticulation

varies with age and material

  • Operates at high pressure
  • Westport uses about twice as much water

per capita than the average

  • Combination of leakage and pressure.
  • Upgrade will address pressure and

possibly the replacement of the trunk main but not the reticulation.

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Proposed Upgrade

  • Council have revisited the Connell Wagner strategic

review

  • Peer reviewed by Opus
  • In addition to peer reviewing the options to upgrade

an operational review was undertaken of the management of the treatment plant process

  • The review by Opus came back with three options
  • Infiltration gallery/ bore field Buller River at Te Kuha
  • Infiltration gallery/ bore field Buller River at Nine

Mile (Reedys)

  • Existing supply upgraded
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Proposed Upgrade

  • Council decision to upgrade the existing

water supply rather than construct from different source.

  • Decision was based on economics and

also sustainability.

  • Proposed upgrade starts at the source

and reviews or renews every component progressively to the start of the reticulation

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Asset Management

  • Council has a GIS

based asset management data base

  • This is still in a development stage

replacing a paper inventory

  • Reticulation is plotted with material type

and age

  • Condition rating is an on going aspect and

is evaluated at time of repairs.

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Asset Management

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Asset Management

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Asset Management

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Westport Water Treatm ent Plant Upgrade

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  • Westport drinking-water supply – A unique

supply with unusual features

  • Why is an upgrade needed?
  • What will the upgrade consist of?

Introduction

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Westport Supply

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Westport Supply

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Westport Supply

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Westport Supply

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Westport Supply

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Existing system

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

Backwash water from reservoir

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Why is an upgrade needed?

  • There have been some problems with water

quality from the treatment plant

  • We know a lot more about water supply

contaminants than we did in 1986

  • Water treatment technology has improved

considerably

  • Legislation introduced in 2007
  • Drinking water standards
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Raw water ponds bypass

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

Backwash water from reservoir Raw water ponds bypass

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Raw water ponds by-pass

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Turbidim eter

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

Backwash water from reservoir Raw water ponds bypass

T

Turbidity meter

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Flocculation tanks

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

Backwash water from reservoir Raw water ponds bypass

T

Turbidity meter Flocculation tanks

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Powdered carbon

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

Backwash water from reservoir Raw water ponds bypass

T

Turbidity meter Flocculation tanks

Powdered carbon

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Filter backwash storage

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

New backwash tank using water that is not pH adjusted Raw water ponds bypass

T

Turbidity meter Flocculation tanks

Powdered carbon

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UV disinfection

Chlorine

storage reservoir Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste Treated water

Lime Coagulant

New backwash tank using water that is not pH adjusted Raw water ponds bypass

T

Turbidity meter Flocculation tanks UV disinfection

Powdered carbon

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New treated water storage reservoir

Chlorine

Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste New treated water storage reservoir

Lime Coagulant

New backwash tank using water that is not pH adjusted Raw water ponds bypass

T

Turbidity meter Flocculation tanks UV disinfection

Powdered carbon

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Filter to waste and pressure m anagem ent

Chlorine

Giles Creek Filters x2 Westport Raw water ponds x3 Orowaiti River Backwash water To waste New treated water storage reservoir

Lime Coagulant

New backwash tank using water that is not pH adjusted Raw water ponds bypass

T

Turbidity meter Flocculation tanks UV disinfection

Powdered carbon

P

Filter to waste Pressure management

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Upgrade consists of

  • Raw water pond bypass
  • Flocculation tanks
  • Powdered carbon
  • Backwash storage
  • UV disinfection
  • New treated water storage reservoir
  • Filter to waste and pressure management
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Tim efram es

  • Detailed design completed

April 2013

  • Tenders evaluated

June 2013

  • Construction begins

September 2013

  • Bulk of works completed

September 2014

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S taged upgrade included in Long Term Plan

2012/ 13 $26,700 Planning, legal & property $130,000 Raw water quality management $700,000 Flocculation tanks $856,700 2013/ 14 $521,000 Filter refurbishment S eismic strengthen $260,000 Filtered water back wash storage $170,000 Filter to waste system $951,000 2014/ 15 $413,000 New plant building monitoring & control $393,500 UV disinfection & buildings $215,000 Alkalinity correction system $375,000 By Pass raw water ponds $1,396,500 2016/ 17 $1,350,000 Enlarge raw water ponds 2018/ 19 $1,500,000 Pipe rest of tunnels 2020/ 21 $2,887,000 Replace trunk main 2022/ 23 $2,400,000 Construct treated water reservoirs 2023/ 24 $610,000 Line raw water reservoirs $11,951,200 Cost estimated in 2012 $ $14,670,329 Cost in LTP adj usted for inflation (BERL Factors) $2,719,129 Inflation

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Financial Impact

Three options:

1.Full upgrade at a cost of $10.3 million defers tunnel piping & lining raw water reservoirs. 2.Part upgrade at a cost of $8.9 million as above but also defers cleaning ot raw water reservoirs 3.Minimum upgrade at a cost of $5.8 million as above but also defers replacing trunk main.

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Upgrade Expense Comparison

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Effect on Westport Targeted Rates

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Effect on Westport Targeted Rates

Westport Targeted Rates (GS T Exclusive)

2014 2015 2016 2017 2018 2019 2020 2021 2022 Full Upgrade $580 $720 $790 $850 $870 $890 $900 $900 $910 Part Upgrade $580 $710 $760 $800 $820 $840 $860 $870 $880 Minimum Upgrade $580 $690 $720 $740 $740 $750 $760 $780 $790

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